Method of making a bladed cylindrical rotor



March 15, 1966 N. LAING 3,239,920

METHOD OF MAKING A BLADED CYLINDRICAL ROTOR Filed March 29, 1965 4 Sheets-Sheet 1 FIG. 1. FIG-2.2.

INVENTOR BY Nlkolqus Lolng ATTOR EYS METHOD OF MAKING A BLADED CYLINDRICAL ROTOR Filed March 29, 1965 4 Sheets-Sheet 2 INVENTOR Nikolous'Loin BYg g W, /%)4 ,,7' .1 M ATTORNEYS (IE1 y 1966 N. LAING 3,239,920

METHOD OF MAKING A BLADED CYLINDRICAL ROTOR Filed March 29, 1965 4 Sheets-Sheet 5 INVENTOR BYNIKO'IQUS Lolng 1 m /%/4 ,7 Ajau- /M ATTORNEYS N. LAING March 15, 1966 METHOD OF MAKING A BLADED CYLINDRICAL ROTOR 4 Sheets-Sheet 4 Filed March 29, 1965 INVENTOR NikolousLoin BYQ g /%74-I ,"j tr-1%;

ATTORNEYS United States Patent Ofiice METHOD OF MAKINg A BLADE!) CYLINDRICAL OTGR Nikolaus Laing, 7141 Aldingen, near Stuttgart, Germany Filed Mar. 29, 1965, Ser. No. 443,588 Claims priority, application Germany, Dec. 7, 1956, L 26,390 11 Claims. (Cl. 29156.8)

This invention relates to bladed cylindrical rotors and to methods of making them. The application is a continuation-in-part of my copending .application No. 221,623 filed September 5, 1962, now abandoned, itself a continuation-in-part of my application No. 671,114 filed July 5, 1957, now abandoned.

The invention is more especially but not exclusively concerned with bladed cylindrical rotors for cross-flow fans, i.e., fans having such a rotor and also guide means co-operating with the rotor on rotation thereof about its axis whereby a flow of air is induced to pass from a suction region through the path of the rotating blades to the interior of the rotor and thence again through the path of the rotating blades to the pressure region, this flow passing generally in planes transverse to the rotor axis. A rotor for a cross-flow fan comprises a series of blades extending longitudinally between end portions, the blades being arranged in a ring about the axis. At least one end portion must provide means for supporting the rotor on a shaft and will normally be of disc-like formation. The other end portion may be annular. If so, then closure means will normally be provided, whether rotating with the rotor or stationary and adjacent thereto, to prevent substantial flow of air through said other end of the rotor.

A main object of the invention is to provide a method of making a rotor for a cross-flow fan, the rotor having the blades, said supporting end portion and an annular portion at the other end all formed in one piece. It is to be understood that to such a one-piece rotor a separate closure means can be secured at said other end if required.

It has been found desirable for a cross-flow rotor to have a large number of blades, in order to improve its efiiciency. More specifically, therefore, the invention aims to provide a method of making a onepiece rotor wherein the sum of the blade depths exceeds the periphery of the outer envelope of the blades.

The term blade depth as used in the specification defines the depth of the blade measured along its crosssectional arc and does not necessarily mean the radial depth between the inner and outer envelopes generated by the inner and outer tips of the blades as the rotor is rotated.

Broadly stated, the invention comprises a method of making a rotor comprising the steps of forming a pot with a bottom and a corrugated side wall, the corrugations running longitudinally of the pot and having a uniform waveform over its periphery, shearing the side walls along lines having a uniform phase relation with the waveform so that the side wall portions between adjacent shear lines embrace 360 of the waveform, the shearing leaving imperforate annular end portions of the pot, and bending the side wall portions between adjacent shear lines to form uniformly oriented concave blades.

The corrugated pot can be formed by drawing or impact-extruding using corrugated dies, or by first drawing or extruding a plain cylindrical pot, and then corrugating it. Various ways are contemplated of shearing the side wall. Thus the pot may be mounted on a mandrel and the side wall indexed past a punch whereby each shear is individually made and the resulting sheared side wall portion bent out by co-operation between the punch 3,239,920 Patented Mar. 15, 1966 and a die having the desired form. Alternatively all shear lines can be formed simultaneously by a plurality of radially-moving knives on to a die of the desired form, the bending once again occurring immediately after shearing.

The phase relation of the shear lines to the waveform is important. In one preferred method, assuming the terminology of A.C. electrical engineering, the shear lines may be at 0, 360 and so on. This allows each blade to be connected to the rotor end portions by a central unsheared portion which is only slightly deformed. Alternatively, the shear lines may be approximately at 90 and 90, and so on so that the outer envelope of the blades lies only slightly beyond that of the pot, this increasing the ratio number of blades circumference of rotor Further features and advantages of the invention will become apparent from the following description of certain embodiments thereof, given by way of example with reference to the somewhat diagrammatic accompanying drawings in which:

FIGURE 1 illustrates in perspective view a pot drawn or extruded with a longitudinally corrugated side wall;

FIGURE 2 illustrates in perspective view a pot drawn or extruded with a plain cylindrical side Wall which is subsequently formed with longitudinal corrugations;

FIGURE 2a illustrates in cross-section how a plain cylindrical side wall may be longitudinally corrugated;

FIGURES 3, 4 and 5 illustrate one means of forming blades in the side wall of a pot such as shown in FIGURE 1 or FIGURE 2, FIGURE 3 being a longitudinal section of the various parts or" the apparatus, and showing a pot in position, FIGURE 4 being a transverse section show ing the pot and the punch and die, and FIGURE 5 being a perspective view of the die;

FIGURES 6 and 7 are partial cross-sectional views of the side walls of two different pots after the formation of blades, showing the relation of the shear lines to the wave form;

FIGURE 8 illustrates in perspective view a rotor formed from a pot as shown in FIGURE 1 and, in position to be assembled therewith, a closure disc for the open end of the rotor; and

FIGURES 9 to 11 illustrate a rotor formed from a pot such as shown in FIGURE 2, FIGURE 9 being a perspective view, FIGURE 10 being a view partly in longitudinal section partly in side elevation and simplified for clarity of illustration, and FIGURE 11 being a cross-sectional view with only some blades shown.

Referring first to FIGURE 1, this figure shows a pot designated generally 1 having a disk-like bottom wall 2 and a side wall 3 formed with longitudinal corrugations 4 over its whole length, the corrugations being of uniform waveform; the waveform here shown is approximately a sine wave referred to a circular datum line, but other Waveforms are contemplated. The bottom wall 2 has a dished central part 5 with a central aperture 5' for mounting the finished rotor on a shaft. The pot shown in FIGURE 1 can be made by deep-drawing sheet material, or by impact-extrusion, in conventional manner except that the dies are corrugated to impart the desired corrugations 4 to the side wall 3.

FIGURE 2, shows a pot, designated generally 10, having a disk-like bottom Wall 11 and a side wall 12 formed with longitudinal corrugations 13 over the major part of its length, these corrugations being similar to the corrugations 4 of FIGURE 1. Top and bottom end portions 14., 15 of the side wall 2 accommodate the transitions be tween the corrugations l3 and respectively the plain circular periphery 16 of the bottom wall 11 where it merges with the side wall 12, and a plain cylindrical rim portion 17 at the open end of the pot. The pot is made by first forming a pot with a bottom wall and a plain cylindrical side wall, in conventional manner by deep-drawing or by impact extrusion, and then forming the corrugations 13 in a separate operation, illustrated in FIGURE 2a. In this operation the pot as drawn or extruded, and having its plain cylindrical side wall shown in FIGURE 2a at 20, is inserted in a die having two separate parts 21, 22 and together presenting an interior wall 23 with longitudinal corrugation 24 which are the female counterpart of the desired corrugations 13. On insertion of the pot into the die the wall is a tight fit on the crests of the corrugations 24. A roller 25 is now inserted into the pot through its open end. The roller 25 has a longitudinally corrugated exterior surface the corrugations 26 whereof are designed to mate with the corrugations 24 on the die parts 21, 22. The roller 25 is driven in an orbital path so as to act as a gear wheel rotating within an interiorly toothed gear ring, thereby deforming the pot side wall 20 to the corrugated form shown in FIGURE 2.. The effective axial extent of the roller 25 corresponds only to the distance shown at h in FIGURE 2. After the roller 25 has passed once or more times around the interior wall 23 of the die parts 21, 22 the latter are separated to permit withdrawal of the rotor.

The corrugated pot, whether in the form hown in FIGURE 1 or in that of FIGURE 2, has now to have its side wall sheared along lines having a uniform phase relation with the waveform of the corrugations, and the side wall portions between adjacent shear lines bent to form uniformly oriented concave blades. Preferably the shearing and bending is done simultaneously by mounting the pot of FIGURE 1 or FIGURE 2 on a specially formed die and moving simultaneously radially towards the pot a series of punches, one for each shear line required, so that all the blades are formed simultaneously by simultaneous shearing and bending. This method is believed to reduce to a minimum the risk of distortion of the pot. However, the shearing and bending can also be performed by indexing the pot past a single punch and die so that each blade is formed in turn, and one method of this type will now be described with reference to FIGURES 3 to 5. In these figures the pot is as shown in FIGURE 2 and similarly designated, but it will be appreciated that with minor changes the method could be used on the pot of FIGURE 1. The orientation of the shear lines with respect to the waveform will not be described with reference to FIGURES 3 to 5 but is to be assumed to be as later described with reference to FIGURE 6, to be discussed later.

The apparatus illustrated in FIGURES 3 to 5 has a substantial base 102 supporting a vertical face plate 103 and a stout horizontal rotatable work support shaft 104. A toothed indexing wheel 10411 is keyed on the shaft 104 and co-operates with locating means 104]). A punch guide 105 is mounted above the base 102. A die carrier 107 is mounted, with the aid of vertical rods 108, for vertical reciprocation in timed relation with the movement of the punch carrier, as will appear.

The punch guide 105 mounts a punch 109 for vertical reciprocation under control of an actuating rod 106. The punch has a knife edge 110 extending parallel to the axis of the work support shaft 104 over the length it of the pot 10 between the top and bottom end portions 14, 15. The knife edge 110 is defined by a plane face 111 at one side and a face 112 on the other which is concave in cross-section (as seen in FIGURE 4) and complementary to the desired form of a rotor blade 200 as seen in crosssection. The die carrier 107 mounts a die 113 which extends within the rotor 10 and presents vertical and arcuate surface 114, 115 respectively opposite to and cooperating with the punch surfaces 111, 112. The die 113 also provides support surface 116 which is formed to lie snugly against the upper part of the inside of the end portion 14 of the pot during punching. A fixed plate 117 secured to the face plate 103 provides a part-cylindrical support edge 117a for the remainder of the pot end portion 14. A removable support disk 1171: may be keyed on the shaft 104, the disk having an edge formed to support the end portion 15 of the pot. The die 113 further includes a support ledge 118 which underlies the formed blades 200 during each punching step. The punch 109 has a surface 109a which locates on a preceding corrugation 13 at each punching step.

In operation the rotor 10 i assembled over the work support shaft 104 and support disk 1171) with the open end located against the face plate 103 on the support edge 117a provided by the plate 117. The disc 104 is caused to rotate with the support shaft during punching. Before each punching step, the die 113 is brought up to abut against the inside of the rotor 10. The punch 109 then descends and severs the wall of the rotor 10 along a line parallel to the axis thereof by the action of the knife edge 110 against the closely adjacent die surface 114. Further downward movement of the punch 109 partially severs and deforms the rotor side wall at the ends of the cut made by the knife edge 110. During this downward movement of the punch 109, the portion of the rotor side wall adjacent the cut is bent down and formed by cooperating surfaces 112, 115 into the desired blade configuration. The surfaces 112, 115 may be slightly rclieved near their ends.

After one punching step, the punch 109 rises and the die 113 drops, and the indexing wheel 104a is rotated an angular distance equal to that separating adjacent blades 200 in the completed rotor 10, and takes the rotor with it. A further punching operation then follows on an adjacent portion of the side wall of the rotor. The sequence of operations is then repeated until all the blades are formed whereupon the completed rotor is removed from the machine.

The rotor is now complete: however closure means may be provided for the open end. A complete rotor made from the FIGURE 1 pot is shown in FIGURE 8 and designated 201. A complete pot made from the FIGURE 2 pot is shown in FIGURES 9 to 11 and designated 202. In each case the blades are designated 200. A closure means is shown in FIGURE 8 in position for assembly with the rotor 201: this closure means has the form of a disc 203 with corrugated edge 204 and an integral flange 205, similarly corrugated, thereon. The closure means may, as shown carry a stub shaft 206 whereby the rotor 201 can be supported for rotation at that end as well as by means of the bottom wall 2. The corrugations on the edge 204 and flange 205 are such that the disc can nest as a press-fit within the open end of the rotor 201 with flange resting on and located by the inturned portions of the blades 200. Alternatively the flange 205 can locate on the outside of the rotor side wall. The rotor 202 can also be provided with closure means, e.g., a plain disc with a cylindrical flange received as a push fit within the end portion 15 and locating on the inturned blade portions. An advantage of the rotor 202 is that an end closure, if required, does not need to be peripherally corrugated and specially oriented to provide a complete closure for the open end of the rotor.

FIGURES 6 and 7 show a portion of the side wall of a partially formed rotor made generally as above described either from the pot 1 of FIGURE 1 or from the pot 10 of FIGURE 2: in each figure the inner and outer envelopes of the corrugations are designated 301, 302 and the inner and outer envelopes of the blades are designated 303, 304. The blades are designated 200 as before, and their inner and outer edges 305, 306: shear lines are shown at 307. In both FIGURE 6 and FIGURE 7 the corrugations are of a similar sine wave, as referred to a circumferential datum line 308, though modifications of such a wave are contemplated. Using the terminology of A.C. electrical engineering, and adopting a zero for the waveform at an arbitrary intersection of the datum line 308, it will be seen that in FIGURE 6 the shear lines 307 come at 0, 360 and so on around the rotor, while in FIGURE 7 the shear lines come at 90, 90 and 90 and so forth. In the FIGURE 6 arrangement a central portion 310 of each blade 200 is only very slightly displaced from the position which it had before shearing and bending, which gives a firm anchorage of the blade to the annular portions of the rotor at either end thereof, and reduces the amount of bending required. However, the orientation of FIGURE 7 also gives a blade portion 311 which is little displaced, though this lies nearer the outer edge 306 of the blade. The advantage of the FIGURE 7 orientation is that the outer blade envelope 304 is only slightly spaced radially from the outer envelope 302 of the corrugations, so that the number of blades per unit of rotor circumference is greater, leading to a correspondingly increased efiiciency in utilization of the rotor in a cross-flow fan. In each case, the sum of the blade depths a, measured along the blade arcs as illustrated exceeds the circumference of the outer envelope 304 of the rotor blades. This of course would be impossible had the blades simply been punched from a plain cylindrical side wall, as in certain prior art constructions.

I claim:

1. A method of making a cylindrical bladed rotor comprising the steps of forming a pot with a bottom and a corrugated side wall from a single piece of material, the corrugations running longitudinally of the pot and having a uniform waveform over its periphery as seen in cross section, shearing the side walls along lines having a uniform phase relation with the waveform so that the side wall portions between adjacent shear lines embrace 360 of the waveform, the shearing leaving annular end portions of the pot, and bending the side Wall portions between adjacent shear lines, to form uniformly oriented concave blades.

2. A method as claimed in claim 1, wherein the pot is formed corrugated from a single piece of sheet material by drawing a pot using corrugated dies.

3. A method as claimed in claim 1, wherein the pot is formed corrugated by impact extrusion using corrugated dies.

4. A method as claimed in claim 1, wherein the pot is formed with a plain cylindrical side wall which is subsequently corrugated.

5. A method as claimed in claim 4, wherein the pot is corrugated by insertion within dies presenting an interiorly corrugated wall, and outwardly pressing the pot side wall against the interior wall of the dies so that the former assumes the corrugations of the latter.

6. A method as claimed in claim 5, wherein the side wall of the pot is pressed against the interior wall of the dies by a corrugated roller rolling over and meshing with said interior wall.

7. A method as claimed in claim 1, wherein the shearing and bending steps are performed by mounting the pot for rotation about its axis with the end portions thereof supported about at least the major part of their periphery, indexing the pot angularly about its axis past a cooperating punch and die both of which are reciprocated and which combine to shear and immediately thereafter to impress the desired blade configurations on successive ones of side wall portions.

8. A method as claimed in claim 1 including the additional step of assembling an end closure member upon the end portion of the pot remote from the bottom thereof.

9. A method of making a hollow single piece cylindrical bladed rotor comprising the steps of forming a longitudinally corrugated pot from a single piece of sheet material wherein the corrugations are substantially sine wave shaped in cross section, shearing the side wall of the pot formed in lines running longitudinally thereof between end portions of the pot left unsheared wherein each said line is at a midpoint between the top and bottom peaks of the rise portion of a sine wave, and bending the portions of the side wall between adjacent shear lines to form blades wherein the portions of the side wall between the midpoint and the top of a wave are bent outwardly of said pot and the portions of the side wall between the midpoint and the bottom of a wave are bent inwardly of said pot.

10. A method of making a bladed cylindrical rotor comprising the steps of forming a pot with a bottom and a corrugated side wall, the corrugations running longitudinally of the pot and having a uniform waveform over its periphery, and shearing the side walls along lines and occurring at regular intervals in the region of alternate mid-points between the outer and inner peaks of the waveform, the shearing leaving imperforate annular end portions of the pot, and bending the side wall portions between adjacent shear lines to form uniformly oriented concave blades.

11. A method of making a bladed cylindrical rotor comprising the steps of forming a pot with a bottom and a corrugated side wall, the corrugations running longitudinally of the pot and having a uniform waveform over its periphery and shearing the side walls along lines occurring at regular intervals in the region of the outer peaks of the waveform, the shearing leaving imperforate annular end portions of the pot, and bending the side wall portions between adjacent shear lines to form uniformly oriented concave blades.

References Cited by the Examiner UNITED STATES PATENTS 1,513,763 11/1924 Rowe. 2,003,981 6/ 1935 Stanitz et a1. 3,008,630 11/1961 Storrs 230134.5

WHITMORE A. WILTZ, Primary Examiner. 

1. A METHOD OF MAKING A CYLINDRICAL BLADED ROTOR COMPRISING THE STEPS OF FORMING A POT WITH A BOTTOM AND A CORRUGATED SIDE WALL FROM A SINGLE PIECE OF MATERIAL, THE CORRUGATIONS RUNNING LONGITUDINALLY OF THE POT AND HAVING A UNIFORM WAVEFORM OVER ITS PERIPHERY AS SEEN IN CROSS SECTION, SHEARING THE SIDE WALLS ALONG LINES HAVING A UNIFORM PHASE RELATION WITH THE WAVEFORM SO THAT THE SIDE WALL PORTIONS BETWEEN ADJACENT SHEAR LINES EMBRACE 360* OF THE WAVEFORM, THE SHEARING LEAVING ANNULAR END PORTIONS OF THE POT, AND BENDING THE SIDE WALL PORTIONS BETWEEN ADJACENT SHEAR LINES, TO FORM UNIFORMLY ORIENTED CONCAVE BLADES. 